Copolymers of ethylene and germinally disubstituted olefins

ABSTRACT

Substantially random ethylene copolymers containing at least 3.0 mole percent of geminally disubstituted olefin monomers are described. The geminally disubstituted olefin monomers can be represented by the generic formula R 1  =R 2  (R 3 )(R 4 ), where R 1  is CH 2 , R 2  is C, and R 3  and R 4  are, independently, essentially linear hydrocarbyl groups having from 1 to 30 carbon atoms, or more, and containing one carbon atom bound directly to R 2 . The copolymers can be prepared by coordination polymerization by means of contacting at least one geminally disubstituted olefin monomer and ethylene, optionally with one or more other coordination polymerizable monomers, with a catalyst system comprising a monocyclopentadienyl, heteroatom-containing Group 4 transition metal catalyst component.

This is a divisional of application Ser. No. 08/651,030, filed 21 May1996, now U.S. Pat. No. 5,763,556.

FIELD OF THE INVENTION

The present invention relates to ethylene copolymers containing at leastone species of seminally disubstituted olefin monomers and apolymerization process for preparing them. More particularly, theinvention is directed to a process for copolymerizing ethylene andgeminally disubstituted olefin monomers in the presence of amonocyclopentadienyl metallocene catalyst component, and the copolymersfrom it.

BACKGROUND OF THE INVENTION

Insertion, or coordination, polymerization is a well-known chemicalreaction sequence for preparing polymers and copolymers of ethylene,α-olefins, non-conjugated diolefins and strained ring cyclic olefins.And, in particular, coordination polymerization withmonocyclopentadienyl metallocene catalyst systems is now well-known.Traditional Ziegler monomers, e.g., ethylene and α-olefins, such aspropylene, 1-butene, 1-hexene, and 1-octene, are readily polymerized inthe presence of Group 4 transition metals having as ligands one η-5bound cydopentadienyl ligand and three σ-bound monoanionic ligands,preferably where one of the monoanionic ligands comprises a heteroatomthat is covalently bound both to the Group 4 metal center and, through abridging group, to a ring carbon atom of the cydopentadienyl ligandgroup.

Geminally disubstituted olefin monomers, such as isobutylene, are knownnot to be readily polymerizable by insertion, or coordination,mechanisms. In the chapter on "Insertion Polymerization", Encycl. ofPolm. Sci. and Eng., vol. 8, p. 175 (Wiley Interscience, 1988), thestatement is made that ". . . 1,1-disubstituted α-olefins are neitherhomo- nor copolymerized with other monoolefins." Instead suchdisubstituted αolefins are typically polymerized and copolymerized bycationic or carbocationic polymerization with Lewis acid catalystsystems known to initiate the formation of carbocations. However, sinceethylene is not readily polymerized by cationic techniques, see Kennedy,J. P., Carbocationic Polymerization of Olefins: A Critical Inventory, p.53 et seq. (John Wiley & Sons, 1975), ethylene copolymers withdisubstituted α-olefns are largely unknown.

In Kennedy and Johnston, Isomerization Polymerization of3-Methyl-1-butene and 4-Methyl-1-pentene, Advances in Polymer Science,p. 58-95 (1975), it was stated to be of interest to examine the cationicisomerization polymerization of 4-methyl-1-pentene because thecompletely isomerized structure can be viewed as a perfectly alternatingcopolymer ethylene and isobutylene. A structure which, in the reporters'words, "cannot be synthesized by conventional techniques", page 61. Dueto multiple isomerization reactions occurring under the cationicisomerization polymerization reactions the sought alternatingethylene-isobutylene was observed, in amounts only up to 55 mol. %--(CH₂ --CH₂ --CH₂ --C(CH₃)₂)-- with the remainder consisting of the 1,2addition product --(CH₂ CH(CH₂ CH(CH₃)₂))-- and the 1,3 addition product--(CH₂ CH₂ CH(CH(CH₃)₂)--. The 1,3-addition product is only possibleusing the cationic chemistries disclosed in the reference and isincompatible with insertion polymerization.

The use of both biscyclopentadienyl and monocyclopentadienyl metallocenecatalyst systems for combined carbocationic and coordinationpolymerization of mixed feeds of ethylene and isobutylene attemperatures below 20° C. is described in WO 95/29940. Copolymerizationof ethylene and isobutylene is said to be enabled by use of thedescribed catalyst systems, in particular, sequential feeding of eachmonomer is said to enable blocky copolymers ofpolyisobutylene-co-polyethylene. Example E describesethylene/isobutylene copolymerization concurrent with thehomopolymerization of both the isobutylene and the ethylene at -20° C.with bis-(cyclopentadienyl)hafnium dimethyl andbis-(pentamethylcyclopentadienyl)-zirconium dimethyl, both activated bytriphenylmethyl-tetrakis(perfluorophenyl)boron. The amount produced ofethylene-isobutylene copolymer was less than 1.3 weight % of the totalpolymer products. Copolymerization of 2-methylpropene (isobutylene) andethylene at 30° C. and 50° C. with ethylene-bis(indenyl)zirconiumdichloride when activated with methylalumoxane was reported in"Isotactic Polymerization of Olefins with Homogeneous ZirconiumCatalysts", W. Kaminsky, et al, Transition Metals and Organometallics asCatalysts for Olefin Polymerization, page 291, 296 (Springer-Verlag,1988). Incorporation of isobutylene was reported to be less than 2.8mol. %, the only example illustrates 1.35 mol. %.

In view of the above, additional means of manufacturing polyolefins,particularly a means of incorporating geminally disubstituted α-olefinsin such polyolefins is highly desirable. Copolymer compositionscomprising ethylene and geminally disubstituted olefins, optionally withother polymerizable olefinically-unsaturated monomers, would provide newcompositions useful in many applications and would serve the function ofeconomically utilizing the inherent feedstock make-up in petroleumrefining processes.

Invention Disclosure

The invention comprises substantially random ethylene copolymers derivedfrom ethylene and at least one geminally disubstituted olefin monomercomprising more than 3.0 mole percent of the geminally disubstitutedolefin monomer. It further comprises a process for the preparation ofthe copolymers comprising contacting the at least one geminallydisubstituted olefin monomer and ethylene, optionally with one or moreother coordination polymerizable monomers, with a catalyst systemcomprising a monocyclopentadienyl, heteroatom ligand-containing Group 4transition metal catalyst component.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a ¹³ C-NMR (62.5 MHz in tol-₈) spectrum of anethylene-isobutylene copolymer of the invention (Example 14). Analysisof the spectrum confirmed a copolymer having segments (--CH₂ --CH₂ --CH₂--CH₂ --CH₂ --C(CH₃)₂ --)_(n) and segments (--CH₂ --CH₂ --CH₂ --C(CH₃)₂--)_(m) in respective amounts of 14 mol. % "n" segments and 85 mol. %"m" segments. No isobutylene diads, or higher homopolymerizedisobutylene segments, are present.

FIG. 2 is a ¹ H-NMR (250 MHz in CDCl₃) spectrum of anotherethylene-isobutylene copolymer of the invention (Example 5). Analysis ofthe spectrum shown indicates that unsaturated chain-end terminationconsists solely of vinylidene groups.

DESCRIPTION OF THE INVENTION AND EXAMPLES

The term "substantially random" when used to describe the ethylenecopolymers of this invention means that the copolymer comprises (A)sequences of an alternating comonomer structure comprising ethylene anda geminally disubstituted olefin monomer randomly interrupted by (B)polyethylene sequences with the characterizing feature that at least oneethylene monomer will be incorporated between each incorporatedgeminally disubstituted olefin monomer. The copolymer may be representedas a copolymer comprising randomly incorporated --(E--G)_(n) -- and--(E)_(b) -- sequences where E represents a (--CH₂ --CH₂ --) unitderived from ethylene and G represents a (--CH₂ --C(R₃)(R₄)--) unitderived from a geminally disubstituted monomer, R₃ and R₄ beingessentially hydrocarbyl radicals as further defined below. The values ofa and b are the respective mole fractions of each unit comprising thecopolymer, where a+b=1. Thus "a" canbe from below 0.03 to 1.00 and "b"can be from 0.00 to 0.97 and higher. Where isobutylene, for example, isavailable as the geminally disubstituted monomer in the reaction processin amounts permitting of high incorporation relative to the ethylene,approaching a 50/50 mol. % ratio, the value of "b" will approach zeroand the polymer will approach astatistically alternating copolymer ofethylene and isobutylene.

The substantially random copolymers according to the invention mayadditionally comprise one or more coordination, or insertion,polymerizable monomers, said monomers being randomly incorporated in theEsequences. For example, a resulting terpolymer may be represented inone embodiment as a copolymer comprising randomly incorporated--(E--G)_(n) --, --(E)_(b) --, and --(T)_(c) sequences where E and G areas described above, T is another coordination polymerizable monomer ormacromer and "a", "b", and "c" are the respective mole fractions of eachsequence comprising the terpolymer. In this embodiment "a" may have avalue of 0.03 to 0.99 while the sum of "b" and "c" may have values of0.01to 0.97, provided that a+b+c=1. Tetrapolymers, etc., will bepossible and each such copolymer will have the characteristic feature ofcomprising the --(E--G)_(a) -- and --(E)_(b) -- sequences, with othersequences depending upon the number of additional polymerizable monomersincorporated.

Geminally disubstituted olefin monomer incorporation in the inventioncopolymer will vary according to process conditions, particularlycomonomer concentrations used in copolymerization but can achieve levelsincluding the low levels taught in the prior art, e.g., from zero (inthe absence of comonomer) to 1.3 or 2.8 mol. %, and can readily exceedthose, e.g., 3.0 to about 50 mol. %. Amounts of from 4 to 45 mol. % areexemplified in this application and are representative. Depending uponthelevel of incorporated seminally disubstituted olefin monomer, ormonomers, polymers ranging from crystalline to elastomeric can beprepared in accordance with the invention. Use of the term "elastomer"or "elastomeric" is meant in this application as recognized in the art,that is the copolymers are largely amorphous, they do not contain asignificantamount of crystalline segments, for example not more than15wt.%. A typicaldescription of elastomeric ethylene-α-olefin copolymerswith respect to crystallinity appears in co-pending application08/545,973, filed Sep. 25, 1995, the teachings of which are incorporatedby reference for purposes of U.S. patent practice. As will be apparentto one of skill in the art, disruption of any polyethylene crystallinestructure, the E units, can also or additionally be achieved by thefurther incorporation of the other coordination polymerization monomerscapable of copolymerization with the polymerization catalyst of theinvention.

The copolymers of the invention will have high degree of terminal,chain-end unsaturation. Those copolymers of the invention having atleast 5 mol. % of geminally disubstituted olefin monomer, will havepredominantly vinylidene chain-end unsaturation. Here predominantlymeans at least 45 mol. % of the total unsaturated chain-ends.

The copolymers of the invention will have an M_(n) (number-averagemolecular weight) value from about 300 to 300,000, preferably betweenfromabout 700 to 200,000, and more preferably less than 100,000. For lowweightmolecular weight applications, such as those copolymers useful inlubricating and fuel oil compositions, an M_(n) of 300 to 20,000 ispreferred, and more preferably less than or equal to 10,000.

Polymerization Process

The generic process for the preparation of the invention copolymerscomprises contacting at least one geminally disubstituted olefin monomerand ethylene, optionally with one or more other coordinationpolymerizablemonomers, with a catalyst system comprising amonocyclopentadienyl, heteroatom-containing Group 4 transition metalcatalyst component. The contacting can be conducted by combining theactivated catalyst composition with the polymerizable monomers undersuitable coordination polymerization conditions. Preferably the catalystcomponent is one additionally comprising a Group 15 or 16 heteroatomcovalently bound both to the Group 4 transition metal center and,through a bridging group, to aring carbon of the cyclopentadienylgroup-containing ligand. Such catalystsare well-known in the art, see,e.g., background U.S. Pat. Nos. 5,055,438, 5,096,867, 5,264,505,5,408,017, 5,504,169 and WO 92/00333. See also, U.S.Pat. Nos. 5,374,696,5,470,993 and 5,494,874; and, see, international publications WO93/19104 and EP 0 514 828 A. For cyclic olefin-containing copolymers,see WO-94/17113, copending U.S. Ser. No. 08/412,507, filed 29 Mar. 1995,U.S. Pat. No. 5,635,573 and copending application U.S. Ser.No.08/487,255, filed Jun. 7, 1995, and published as WO 96/002444.Additionally, the unbridged monocyclopentadienyl, heteroatom-containingGroup 4 transition metal catalyst components of copending U.S. patentapplication 08/545,973, filed Sep. 25, 1995, will be suitable inaccordance with the invention. Each of the foregoing references areincorporated by reference for the purposes of U.S. patent practice.

Without intending to limit the invention, it is believed that a catalyststructure, exemplified and described in both the documents above and inthe description and examples below, acts to allow ready polymerizationof the geminally disubstituted olefins, but principally from theunhindered approaches to the metal coordination center and in a mannerdictated by the steric constraints of the catalyst compound ligandsystem and the steric structure of the geminally disubstituted olefins.The bulk or steric structure of an inserted geminally disubstitutedolefin and the steric constraints of the catalyst ligand system duringinsertion may act to inhibit entry into the coordination center of thecatalyst of an immediately subsequent geminally disubstituted olefinmonomer. Thus insertion of a subsequent geminally disubstituted olefinis generally preceded by the insertion of ethylene. The subsequentgeminally disubstituted olefin is then not inhibited by the previouslyinserted ethylene and can readily enter and be inserted. A copolymerresults havingthe described sequence segments containing those that areessentially of alternating G units. As an apparent result, the inventioncopolymer has aninsignificant number of, that is essentially no, diads,triads, etc., comprising homopolymerized, or sequentially polymerized,geminally disubstituted olefins.

The optional coordination polymerizable monomers that may beincorporated in the substantially random ethylene copolymers will alsobe randomly incorporated at the beginning or within the E sequences ofthe invention copolymer.

The geminally disubstituted olefins useful in accordance with theinventioninclude essentially any having the generic formula

    R.sub.1 =R.sub.2 (R.sub.3)(R.sub.4),

where R₁ is CH₂, R₂ is C, and R₃ and R₄ are, independently, essentiallyhydrocarbyl groups containing at least one carbon atom bound to R₂.Preferably R₃ and R₄ are linear, branched or cyclic, substituted orunsubstituted, hydrocarbyl groups having from 1 to 100 carbon atoms,preferably 30 or less carbon atoms, andoptionally R₃ and R₄ areconnected to form a cyclic structure. Thus the term geminallydisubstituted olefins includes both monomers, suchas isobutylene, andmacromers having the representative structure above. Though R₃ and R₄are to be essentially hydrocarbyl, the inclusion of non-hydrocarbylatoms (such as O, S, N, P, Si, halogen etc.) is contemplated where suchare sufficiently far removed from the double-bond so as not to interferewith the coordination polymerization reactions with the catalyst and soas to retain the essentially hydrocarbyl characteristic of being largelysoluble in hydrocarbon solvents. The geminally substituted olefinsspecifically include isobutylene, 3-trimethylsilyl-2-methyl-1-propene,2-methyl-1-butene, 2-methyl-1-pentene, 2-ethyl-1-pentene,2-methyl-1-hexene, 2-methyl-1-heptene,6-dimethylamino-2-methyl-1-hexene, α-methylstyrene and the like asrepresentative compounds.

The optional coordination polymerizable monomers which may becopolymerizedin accordance with the invention include one or more of: C₃and higher α-olefins, styrene and hydrocarbyl-substituted styrenemonomers wherein the substituent is on the aromatic ring, C₆ and highersubstituted α-olefins, C₄ and higher internal olefins, C₄ and higherdiolefins, C₅ and higher cyclic olefins and diolefins, andacetylenicallyunsaturated monomers. Preferred α-olefins include α-olefins having 3 to30 carbon atoms, preferably 3 to 20 carbon atoms, but 1-olefin macromershaving more than 30 carbon atoms, up to about 100 carbons atoms and morecan similarly be used.

Preferred α-olefins thus include propylene, 1-butene, 1-pentene,1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene,4-methyl-1-pentene, 5-methyl-1-nonene, 3-methyl-1-pentene,3,5,5-trimethyl-1-hexene, and vinylcyclohexane. Styrene andparamethylstyrene are preferred styrenic olefins. Preferred diolefinsinclude those described in the literature for ethylene copolymers,specifically for EPDM rubber, the disclosure of copending application08/545,973, above, is particularly relevant in this regard. Examplesinclude straight chain acyclic diolefins, branched acyclic diolefins,single ring alicyclic diolefins, multi-ring alicyclic fused and bridgedring diolefins and cycloalkenyl-substituted alkenes. Preferred examplesare 1,4-hexadiene, dicyclopentadiene, 5-ethylidene-2-norbornene,vinylcyclohexene and 5-vinyl-2-norbornene.

The C₆ and higher substituted α-olefins include those containingat leastone Group 13 to 17 atom bound to a carbon atom of the substitutedα-olefin. Examples include allyltrimethylsilane,4,4,4-trifluoro-1-butene, methyl allyl ether, methyl allyl thiother, anddimethyl allyl amine. The use of functional group-containing α-olefinsis also within the scope of the invention when such olefins can beincorporated in the same manner as are their α-olefinanalogs. See,"Metallocene Catalysts and Borane Reagents in The Block/GraftReactionsof Polyolefins", T. C. Chung, et al, Polym. Mater. Sci. Eng., v. 73, p.463 (1995), and the masked α-olefin monomers of U.S. Pat. No.5,153,282.Such monomers permit the preparation of both functional-group containinginvention copolymers capable of subsequent derivatization and offunctional macromers which can be used as graft and block type polymericsegments. All documents are incorporated by reference for purposes ofU.S. patent practice.

Cyclic olefins capable of copolymerization in accordance with theinventioninclude cyclopentene, norbornene, alkyl-substitutednorbornenes, cyclohexene, cycloheptene and those further described inthe background documents and patent literature, see WO-94/17113,copending U.S. Ser. No. 08/412,507, filed 29 Mar. 1995, and U.S. Pat.Nos. 5,270,393 and 5,324,801. These documents are as well incorporatedby reference for purposes of U.S. patent practice.

For the copolymerization of geminally disubstituted olefins withethylene, the preferred molar ratio of geminally disubstituted olefin toethylene isfrom about 1000:1 to 1:1000, more preferably from about 500:1to 1:20, evenmore preferably from 100:1 to 1:1. The optionalcoordination polymerizable monomers may be introduced in any ratioconsistent with desired incorporation ratios.

The monocyclopentadienyl, heteroatom-containing Group 4 transition metalcatalyst components of the invention are derived from themonocydopentadienyl Group 4 metallocene compounds well-known anddescribedin the documents listed above, and others in the patentliterature. These compounds may be represented by the generic formula##STR1##wherein: M is Zr, Hf or Ti, preferably Ti;

Cp is a cyclopentadienyl ring which may be substituted with from zero tofive substituted groups R when y is zero, and from one to foursubstitutedgroups R when y is one; and each substituted group R is,independently, a radical selected from hydrocarbyl, silyl-hydrocarbyl orgermyl-hydrocarbylhaving from 1 to 30 carbon, silicon or germaniumatoms, substituted hydrocarbyl, silyl-hydrocarbyl or germyl-hydrocarbylradicals as defined wherein one or more hydrogen atoms is replaced by ahalogen radical, an amido radical, a phosphido radical, an alkoxyradical, an aryloxy radical or any other radical containing a Lewisacidic or basic functionality; C₁ to C₃₀ hydrocarbyl-substitutedmetalloid radicals wherein themetalloid is selected from the Group 14 ofthe Periodic Table of Elements; halogen radicals; amido radicals;phosphido radicals; alkoxy radicals; or alkylborido radicals; or, Cp isa cyclopentadienyl ring in which at least two adjacent R-groups arejoined together and along with the carbon atoms to which they areattached form a C₄ to C₂₀ ring system which may be saturated, partiallyunsaturated or aromatic, and substituted or unsubstituted thesubstitutions being selected as one or more R group as defined above;

J is a Group 15 or 16 heteroatom which may be substituted with one R'groupwhen J is a group 15 element, and y is one, or a group 16 elementand y is zero, or with two R' groups when J is a group 15 element and yis zero, oris unsubstituted when J is Group 16 element and y is one; andeach substituent group R' is, independently, a radical selected from:hydrocarbyl, silyl-hydrocarbyl or germyl-hydrocarbyl radicals having 1to 30 carbon, silicon or germanium atoms; substituted hydrocarbyl,silyl-hydrocarbyl or germyl-hydrocarbyl radicals as defined wherein oneormore hydrogen atoms is replaced by a halogen radical, an amidoradical, a phosphido radical, an alkoxy radical, or an aryloxy radical;halogen radicals; amido radicals; phosphido radicals; alkoxy radicals;or alkylborido radicals;

each X is independently a monoanionic ligand selected from hydride;substituted or unsubstituted C₁ to C₃₀ hydrocarbyl; alkoxide; aryloxide;amide; halide or phosphide; Group 14 organometalloids; or both X'stogether may form an alkylidene or a cyclometallated hydrocarbyl or anyother dianionic ligand;

y is 0 or 1; and when y=1,

A' is a bridging group covalently bonded to both Cp and J, typicallycomprising at least one Group 13, 14 or 15 element such as carbon,silicon, boron, germanium, nitrogen or phosphorous with additionalsubstituents R as defined above so as to complete the valency of theGroup13, 14 or 15 element(s);

L is a neutral Lewis base other than water, such as an olefin, diolefin,aryne, amine, phosphine, ether or sulfide, e.g., diethylether,tetrahydrofuran, dimethylaniline, aniline, trimethylphosphine,n-butylamine, and the like; and,

w is a number from 0 to 3.

Preferred compounds include:dimethylsilyl(tetramethylcyclopentadienyl)(cyclododecylamido)titaniumdichloride,dimethylsilyl(tetramethylydopentadienyl)cycldodecyloamido)titaniumdimethyl,dimethylsily(tetramethylcydopentadienyl)(1-adamantylamido)titaniumdichloride,dimethylsilyl(tetra-methylcyclo-pentadienyl)(1-adamantylamido)titaniumdimethyl,dimethylsilyl(tetramethylcydopentadienyl)(t-butylamido)titaniumdichloride,dimethylsilyl(tetramethylcyclopentadienyl)(t-butylamido)titaniumdimethyl.The zirconium and hafnium analogs to the above compounds willalso be preferred, but the titanium versions are more highly preferred.

Additionally, such compounds include the dimeric species that resultfrom dimerizing two of the monocyclopentadienyl, heteroatom-containingGroup 4 transition metal catalyst compounds described, as is well knownand described in the documents above.

The term "cyclopentadienyl" refers to a 5-member ring having delocalizedbonding within the ring and typically being bound to M through η⁵-bonds,carbon typically making up the majority of the 5-member positions.

The monocyclopentadienyl catalyst compounds according to the inventionmay be activated for polymerization catalysis in any manner sufficientto allow coordination polymerization. This can be achieved for examplewhen one X ligand can be abstracted and the other X will either allowinsertionof the unsaturated monomers or will be similarly abstractablefor replacement with an X that allows insertion of the unsaturatedmonomer. The traditional activators of metallocene polymerization artare suitable,those typically include Lewis acids such as alumoxanecompounds, and ionizing, anion pre-cursor compounds that abstract one Xso as ionize the transition metal center into a cation and provide acounter-balancing, compatible, noncoordinating anion.

Alkylalumoxanes and modified alkylalumoxanes are suitable as catalystactivators, particularly for the invention metal compounds comprisinghalide ligands. The alumoxane component useful as catalyst activatortypically is an oligomeric aluminum compound represented by the generalformula (R"--A1--O).sub.η, which is a cyclic compound, orR"(R"--A1--O).sub.η A1R"₂, which is a linear compound. In the generalalumoxane formula R" is independently a C₁ to C₁₀ alkyl radical, forexample, methyl, ethyl, propyl, butyl or pentyl and "n" is anintegerfrom 1 to about 50. Most preferably, R" is methyl and "n" is at least 4.Alumoxanes can be prepared by various procedures known in the art. Forexample, an aluminum alkyl may be treated with water dissolved inaninert organic solvent, or it may be contacted with a hydrated salt,suchas hydrated copper sulfate suspended in an inert organic solvent, toyield an alumoxane. Generally, however prepared, the reaction of analuminum alkyl with a limited amount of water yields a mixture of thelinear and cyclic species of the alumoxane. Methylalumoxane and modifiedmethylalumoxanes are preferred. For further descriptions see, U.S. Pat.Nos. 4,665,208, 4,952,540, 5,041,584, 5,091,352, 5,206,199, 5,204,419,4,874,734, 4,924,018, 4,908,463, 4,968,827, 5,329,032, 5,248,801,5,235,081, 5,157,137, 5,103,031 and EP 0 561476 A1, EP 0 279 586 B1, EP0 516 476 A, EP 0 594 218 A1 and WO 94/10180, each being incorporated byreference for purposes of U.S. patent practice.

When the activator is an alumoxane, the preferred transition metalcompoundto activator molar ratio is from 1:2000 to 10:1, more preferablyfrom about1:500 to 10:1, even more preferably from about 1:250 to 1:1and most preferably from about 1:100 to 1:1.

The term "noncoordinating anion" as used for the ionizing, anionpre-cursorcompounds is recognized to mean an anion which either does notcoordinate to said transition metal cation or which is only weaklycoordinated to said cation thereby remaining sufficiently labile to bedisplaced by a neutral Lewis base. "Compatible" noncoordinating anionsare those which are not degraded to neutrality when the initially formedcomplex between the monocyclopentadienyl catalyst compounds and theionizing, anion pre-cursor compounds decomposes. Further, the anion willnot transfer an anionic substituent or fragment to the cation so as tocause it to form a neutral four coordinate metallocene compound and aneutral by-product fromthe anion. Noncoordinating anions useful inaccordance with this invention are those which are compatible, stabilizethe metallocene cation in the sense of balancing its ionic charge in a+1 state, yet retain sufficient lability to permit displacement by anolefinically or acetylenically unsaturated monomer duringpolymerization. Additionally, the anions usefulin this invention will belarge or bulky in the sense of sufficient molecular size to partiallyinhibit or help to prevent neutralization of the metallocene cation byLewis bases other than the polymerizable monomers that may be present inthe polymerization process. Typically the anion will have a molecularsize of greater than or equal to about 4 angstroms.

Descriptions of ionic catalysts, those comprising a transition metalcationand a non-coordinating anion, suitable for coordinationpolymerization appear in the early work in U.S. Pat. Nos. 5,064,802,5,132,380, 5,198,401, 5,278,119, 5,321,106, 5,347,024, 5,408,017, WO92/00333 and WO 93/14132. These teach a preferred method of preparationwherein metallocenes (including monoCp metallocenes) are protonated byan anion precursors such that an alkyl/hydride group is abstracted froma transition metal to make it both cationic and charge-balanced by thenon-coordinating anion.

The use of ionizing ionic compounds not containing an active proton butcapable of producing both the active metallocene cation and annoncoordinating anion is also known. See, EP-A-0 426 637, EP-A-0 573 403and U.S. Pat. No. 5,387,568. Reactive cations other than the Bronstedacids include ferrocenium, silver, tropylium, triphenylcarbenium andtriethylsilylium, or alkali metal or alkaline earth metal cations suchas sodium, magnesium or lithium cations. A further class ofnoncoordinating anion precursors suitable in accordance with thisinvention are hydrated salts comprising the alkali metal or alkalineearth metal cations and a non-coordinating anion as described above. Thehydrated salts can be prepared by reaction of the metalcation-non-coordinating anion salt with water, for example, byhydrolysis of the commercially available or readilysynthesized LiB(pfp)₄which yields Li•xH₂ O! B(pfp)₄ !, where (pfp) is pentafluorophenyl orperfluorophenyl.

Any metal or metalloid capable of forming a coordination complex whichis resistant to degradation by water (or other Bronsted or Lewis Acids)may be used or contained in the anion. Suitable metals include, but arenot limited to, aluminum, gold, platinum and the like. Suitablemetalloids include, but are not limited to, boron, phosphorus, siliconand the like. The description of non-coordinating anions and precursorsthereto of the documents of the foregoing paragraphs are incorporated byreference for purposes of U.S. patent practice.

An additional method of making the ionic catalysts uses ionizing anionprecursors which are initially neutral Lewis acids but form the cationandanion upon ionizing reaction with the metallocene compounds, forexample tris(pentafluorophenyl) boron acts to abstract a hydrocarbyl,hydride or silyl ligand to yield a metallocene cation and stabilizingnon-coordinating anion, see EP-A-0 427 697 and EP-A-0 520 732. Ioniccatalysts for coordination polymerization can also be prepared byoxidation of the metal centers of transition metal compounds by anionicprecursors containing metallic oxidizing groups along with the aniongroups, see EP-A-0 495 375. The description of non-coordinating anionsandprecursors thereto of these documents are similarly incorporated byreference for purposes of U.S. patent practice.

When the cation portion of an ionic non-coordinating precursor is aBronsted acid such as protons or protonated Lewis bases (excludingwater),or a reducible Lewis acid such as ferricinium or silver cations,or alkaline metal or alkaline earth metal cations such as those ofsodium, magnesium or lithium cations, the transition metal to activatormolar ratio may be any ratio, but preferably from about 10:1 to 1:10,more preferably from about 5:1 to 1:5, even more preferably from about2:1 to 1:2 and most preferably from about 1.2:1 to 1:1.2 with the ratioof about 1:1 being the most preferred.

Since the geminally disubstituted olefins will tend to be polymerizedcarbocationically independently of the ethylene, and of many othercoordination polymerizable monomers, when in the presence of a stablecarbocation such as tropylium, triphenylcarbenium, hydrated alkalinemetalor alkaline earth metals, or Lewis acids strong enough to liberatea protonfrom water, for example trispentafluorophenyl) boron, the aboveratios are preferred only when the reaction system is essentially freeof compounds capable of generating a proton, such as water or alcohols.If trace quantities of these compounds are present, the preferredtransition metal compound to activator molar ratio is from 10:1 to 1:1,more preferably from about 5:1 to 1:1, even more preferably from about2:1 to 1:1 and mostpreferably from about 1.2:1 to 1:1 with the ratio of1.05:1 being the most preferred.

When the X ligands are not hydride, hydrocarbyl or silylhydrocarbyl,such as the chloride ligands indimethylsilyl(tetramethylcyclopentadienyl(phenethylamido)titaniumdichloride, and are not capable of discrete ionizing abstraction withthe ionizing, anion pre-cursor compounds, the X ligands can be convertedvia known alkylation reactions with organometallic compounds such aslithium or aluminum hydrides or alkyls, alkylalumoxanes, Grignardreagents, etc. See EP-A-0 500 944, EP-A1-0 570 982 and EP-A1-0 612 768for processes describing the reaction of alkyl aluminum compounds withdihalide substituted metallocene compounds prior to or with the additionof activating noncoordinating anion precursor compounds. Accordingly, apreferred catalytically active monocyclopentadienyl,heteroatom-containingGroup 4 transition metal catalyst component is atransition metal cation stabilized and counter-balanced with anon-coordinating anion as derived in any of the foregoing methods.

When using ionic catalysts comprising the invention Group 4 metalcations and non-coordinating anions, the total catalyst system willgenerally additionally comprise one or more scavenging compounds. Theterm "scavenging compounds" as used in this application and its claimsis meantto include those compounds effective for removing polarimpurities from thereaction environment. The term will also includeproton scavengers to suppress competing carbocationic polymerization,see the description and illustrations of WO 95/29940. Impurities can beinadvertently introduced with any of the polymerization reactioncomponents, particularly with solvent, monomer and catalyst feed, andadversely affect catalyst activityand stability. It can result indecreasing or even elimination of catalyticactivity, particularly when ametallocene cation-noncoordinating anion pairis the catalyst system. Thepolar impurities, or catalyst poisons include water, oxygen, metalimpurities, etc. Preferably steps are taken before provision of suchinto the reaction vessel, for example by chemical treatment or carefulseparation techniques after or during the synthesis or preparation ofthe various components, but some minor amounts of scavenging compoundwill still normally be used in the polymerization process itself.

Typically the scavenging compound will be an organometallic compoundsuch as the Group-13 organometallic compounds of U.S. Pat. Nos.5,153,157, 5,241,025 and WO-A-91/09882, WO-A-94/03506, WO-A-93/14132,and that of WO 95/07941. Exemplary compounds include triethyl aluminum,triethyl borane, triisobutyl aluminum, methylalumoxane, isobutylaluminumoxane, and n-octylaluminum. Those scavenging compounds havingbulky or C₈ -C₂₀ linear hydrocarbyl substituents covalently bound to themetal or metalloidcenter being preferred to minimize adverse interactionwith the active catalyst. When alumoxane is used as activator, anyexcess over the amount of metallocene present will act as scavengercompounds and additional scavenging compounds may not be necessary. Theamount of scavenging agent to be used with metallocenecation-noncoordinating anion pairs is minimized during polymerizationreactions to that amount effective to enhance activity.

The catalyst according to the invention may be supported for use in gasphase, bulk, slurry polymerization processes, or otherwise as needed.Numerous methods of support are known in the art for copolymerizationprocesses for olefins, particularly for catalysts activated byalumoxanes,any is suitable for the invention process in its broadestscope. See, for example, U.S. Pat. Nos. 5,057,475 and 5,227,440. Anexample of supported ionic catalysts appears in WO 94/03056. Aparticularly effective method isthat described in co-pending applicationU.S. Ser. No. 08/474,948 filed Jun. 7, 1995, now U.S. Pat. No. 5,643,847and WO 96/04319. A bulk, or slurry, process utilizing supported,bis-cyclopentadienyl Group 4 metallocenes activated with alumoxaneco-catalysts is described as suitable for ethylene-propylene rubber inU.S. Pat. Nos. 5,001,205 and 5,229,478, these processes willadditionally be suitable with the catalystsystems of this application.Both inorganic oxide and polymeric supports may be utilized inaccordance with the knowledge in the field. See U.S. Pat. Nos.5,422,325, 5,427,991, 5,498,582, 5,466,649, copending U.S. patentaplications 08/265,532 now abandoned and 08/265,533, now abandoned bothfiled Jun. 24, 1995, and international publications WO 93/11172 and WO94/07928. Each of the foregoing documents is incorporated by referencefor purposes of U.S. patent practice.

In preferred embodiments of the process for this invention, the catalystsystem is employed in liquid phase (solution, slurry, suspension, bulkphase or combinations thereof), in high pressure liquid or supercriticalfluid phase, or in gas phase. Each of these processes may be employed insingular, parallel or series reactors. The liquid processes comprisecontacting the ethylene and geminally disubstituted olefin monomers withthe above described catalyst system in a suitable diluent or solvent andallowing said monomers to react for a sufficient time to produce theinvention copolymers. Hydrocarbyl solvents are suitable, both aliphaticand aromatic, hexane and toluene are preferred. Bulk and slurryprocesses are typically done by contacting the catalysts with a slurryof liquid monomer, the catalyst system being supported. Gas phaseprocesses similarly use a supported catalyst and are conducted in anymanner known to be suitable for for ethylene homopolymers or copolymersprepared by coordination polymerization. Illustrative examples may befound in U.S. Pat. Nos. 4,543,399, 4,588,790, 5,028,670, 5,382,638,5352,749, 5,436,304,5,453,471, and 5,463,999, and WO 95/07942. Each isincorporated by reference for purposes of U.S. patent practice.

Generally speaking the polymerization reaction temperature can vary fromabout -50° C. to about 250° C. Preferably the reaction temperatureconditions will be from -20° C. to 220°, more preferably below 200° C.The pressure can vary from about 1 mm Hg to 2500 bar, preferably from0.1 bar to 1600 bar, most preferably from 1.0to 500 bar. Where lowermolecular weight copolymers, e.g., M_(n) ≦10,000, are sought it will besuitable to conduct the reaction processes at temperatures above about0° C. and pressures under 500bar. The multiboron activators of U.S. Pat.No. 5,278,119 can additionally be employed to facilitate the preparationof the low molecular weight copolymers of the invention.

As will be apparent to those skilled in the art the catalyst compoundsand components of this invention may be mixed with other catalystsystems or used with series or parallel reactors employing one or moresuch catalyst systems to prepare polymer blends comprising one or moreof invention copolymers or blends of them with other polymers andcopolymers with properties associated with such blends, for example,broadened polydispersity for improved processing polymer compositionsand improved impact strength polymer blend compositions.

Industrial Applicability

Low molecular weight α-olefin-containing copolymers are known to beuseful as petroleum product additives and as components of adhesive andsealant compositions. This is particularly true when functionalizationthrough terminal unsaturation in such copolymers is feasible. And, sincepetroleum refining produces feedstreams that can be separated byfractionation into those comprising lower carbon number compounds (from2 to 4 carbons), from those of higher carbon number compounds (five andabove), and since the lower carbon number compounds will comprise bothα-olefins and isobutylene, the ability to incorporate the isobutylenealong with its analogs, 1-butene and 2-butene, contained in thosefeedstreams is industrially desired. See, for example, WO 93/24539,where isobutylene is apparently used as an unreactive diluent unless acarbocationic catalyst is added with the biscyclopentadienyl metallocenecoordination catalysts.

The copolymers of the invention will be useful in low molecular weightembodiments as oleaginous composition modifiers, for example, fuel orlubricating oil additives, particularly when essentially elastomeric andhaving significant amounts of terminal vinylidene groups. See U.S. Pat.No. 5,498,809 and international publications WO 94/19436 and WO 94/13715for description of ethylene-1-butene polymers having at least 30%vinylidene termination, and their functionalization into effectivedispersants for lubricating oil compositions. Such compositions are saidto be suitable replacements in lubricating oil compositions fortraditionally used dispersants comprising functionally modifiedpolyisobutylene. See also, EP 0 513 211 B1 where similar copolymers aredescribed in effective wax crystal modifier compositions for use in fuelcompositions. All references are incorporated by reference for purposesofU.S. patent practice.

Additional uses will arise in fields traditionally using similarmolecular weight ethylene-α-olefin copolymers of at least some ethylenecrystallinity, such as linear low density and low density polyethylenecopolymers of ethylene with 1-butene, 1-hexene or 1-octene. Films andpackaging materials can be prepared from such copolymers by methodswell-known in the art. Additionally, adhesive compositions can bepreparedusing the invention copolymers as replacements for higherα-olefin content copolymers prepared with metallocene catalysts,particularly thosedescribed as plastomers because of their elastomericproperties. As known in the art, such copolymers can be used as basepolymers that with the addition of tackifier resins, waxes orplasticizers constitute adhesive compositions useful inpressure-sensitive adhesive compositions, hot melt adhesive compositionsand the like. See, for example, co-pending U.S. application Ser. Nos.08/410,656, filed Mar. 24, 1996, U.S. Pat. No. 5,530,054 and 08/406,832,filed Mar. 20, 1995 U.S. Pat. No. 5,548,014 and their Internationalcounterparts WO 92/12212 and WO 94/10256, each is incorporated byreference for purposes of U.S. patent practice.

EXAMPLES

In order to illustrate the present invention, the following examples areprovided. Such are not meant to limit the invention in any respect, butare solely provided for illustration purposes.

The properties of the polymer were determined by the following testmethods:

All molecular weights are weight average molecular weight unlessotherwise noted. Molecular weights (weight average molecular weight(M_(w)) and number average molecular weight (M_(n)) were measured by GelPermeation Chromatography, unless otherwise noted, using a Waters 150Gel Permeation Chromatograph equipped with a differential refractiveindex detector and calibrated using polystyrene standards. Samples wererun in either THF (45° C.) or in 1,2,4-trichlorobenzene (145° C.)depending upon the sample's solubility using three Shodex GPC AT-80 M/Scolumns in series. This general technique is discussed in "LiquidChromatography of Polymers and Related Materials III" J. Cazes Ed.,Marcel Decker, 1981, page 207, which is incorporated by reference forpurposes of U.S. patent practice herein. No corrections for columnspreading were employed; however, data on generally accepted standards,e.g. National Bureau of Standards Polyethylene 1475, demonstrated aprecision with 0.1 units for M_(w) /M_(n) which was calculated fromelution times. The numerical analyses were performed using Expert Easesoftware available from Waters Corporation.

All polymerizations were carried out under nitrogen using anhydroussolvents. Isobutylene and 2-methyl-1-pentene were dried by passing thevapor or liquid through columns packed with barium oxide and, forisobutylene, condensing the gas in a bath cooled to below the boilingpoint of isobutylene (b.p. ˜-10° C.). Ethylene was purchased in 99.9%purity and used as received. Solvent and scavenger, if used,werecombined directly into the reaction vessel at ambient pressure andallowed to mix for at least 5 minutes prior to the introduction ofisobutylene. Isobutylene was collected as a condensed liquid. A knownvolume of isobutylene was added to the reactor at a temperature belowits boiling point or forced into the reactor with pressure from apressurized cylinder. Ethylene was added to the reactor as a gas at apredetermined pressure. Propylene was similarly added in Example 18. The2-methyl-1-pentene was added through a reaction inlet as a liquid. Thepressures listed in the tables are differential pressures defined as thedifference between the nascent reactor pressure before ethylene additionand the ethylene gauge pressure. Catalysts were activated outside of thereactor in a small volume of toluene (˜2 ml) and added to the reactorwith back pressure.

M_(n) values are reported as polystyrene equivalents. ¹ H- and decoupled¹³ C-NMR spectroscopic analyses were run in either CDCl₃ or toluene-d₈at ambient temperature using a field strength of 250 MHz (¹³ C - 63 MHz)or in tetrachloroethane-d₂ at 120° C. using a field strength of 500 MHz(¹³ C - 125 MHz) depending upon the sample's solubility. Incorporation(mol %) of isobutylene into the copolymers of all examples except 17 and18 was determined by comparison the integration of the methyl protonresonances with those of the methylene proton resonances using theequation below.

    mol % IB=100×(4A)/(6B+2A)

where: A: integration of the methyl resonances B: integration of themethylene resonances

For examples 17 and 18 incorporation was determined by ¹³ C-NMR.

Examples 1 and 2

Example 2 is described here as an example, Example 1 was run in the samemanner except without the proton scavenger. Hexane (20 ml) and 0.04 ml(0.000178 mol) of 2,6-di-tert-butylpyridine (DTBP) were added to themain chamber of the reactor. This was cooled to -20° C. whereupon 20 mlof isobutylene was added. The chamber was sealed and warmed toapproximately 28° C. To 2 ml of toluene, 68 mg ofdimethylsilyl(pentamethylcyclopentadienyl)(cyclododecylamido)titaniumdimethyl and 144 mg of Ph₃ CB(PfP)₄ were dissolved and reacted. Afterthree minutes, the solution was syringed into the catalyst additionport. The port was opened with nitrogen pressure and was immediatelyfollowed with ethylene to raise the reactor pressure an additional 65psi.Reaction was continued for 10 more minutes. The reactor was thende-pressurized and methanol was added to terminate the polymerization.Polymer was isolated by methanol precipitation. The polymer was washedwith additional methanol and dried in vacuo.

Examples 3-6

Polymerizations were run similarly to that described above, except thatdimethylanilinium tetrakisperfluorophenylboron was used as theactivator.

Examples 7-10

These examples are similar in scope to those described above except fortheuse of triethylaluminum (TEAL) as a scavenger and the manner in whichisobutylene is added to the reactor. A typical example follows. Thereactor was charged with 100 ml of hexane and 0.2 ml of a 0.25 wt.% TEALsolution in toluene under nitrogen. This solution was stirred forseveral minutes. Isobutylene (100 ml) was poured into a stainless steelsample cylinder at -80° C. The cylinder was weighed and warmed toambient temperature and then vertically connected to the reactor. Thenascent pressure in this cylinder was used to force the liquid from thesample cylinder into the solution contained in the sealed reactor. Oncetransfer was complete, the sample cylinder was removed and re-weighed todetermine the efficiency of the transfer. In all cases, transfer wasmore than 95% complete. The reactor was equilibrated to the desiredreaction temperatureand maintained at this temperature unless otherwisereported. Catalyst was activated in ˜4 ml of toluene (40 mgdimethylsilylpentamethylcyclopentadienyl)(cyclododecylamido)dimethyltitanium and 74 mg dimethylanilinium tetrakisperfluorophenylboron andadded to the reactor with a pressurized back wash of hexane. Thisadditionwas immediately followed by the addition of ethylene to bringthe reactor pressure to 65 psi above the pressure before the additions.Reaction was allowed to proceed for a the reported predetermined timebefore de-pressurization of the reactor and quenching of the reactionwith methanol. Polymer was isolated and purified as before.

                                      TABLE 1    __________________________________________________________________________    Polymerization Conditions with    Dimethylsilyl (pentamethylcyclopentadienyl) (N-cyclododecylamido)    titanium dimethyl         Temperature               Catalyst                      Activator                              Solvent,                                     IB! Ethylene                                              time                                                  Yield    Example         (°C.)                cat.!, (mol/L)                       act.!, (mol/L)                              volume (ml)                                    (mol/L)                                         (psi)                                              (min.)                                                  (grams)    __________________________________________________________________________    Hexane    1    21→35               0.0039 D, 0.0039                              20    6.3  65   10  0.95    2.sup.a         27.8→74               0.0039 D, 0.0039                              20    6.3  65   10  4.8    3.sup.a         21→21.4               0.0039 A, 0.0011                              20    6.3  65   10  0.11    4.sup.a         21→21.2               0.0011 A, 0.0011                              20    6.3  65   6   0.05    5    21.3→40               0.0039 A, 0.0039                              20    6.3  65   5   1.7    6    25→28               0.0039 .sup. A, 0.0039.sup.d                              20    6.3  65   5   0.7    7    ˜36               0.0018 A, 0.0018                              100   6.3  65   10  10.0    8.sup.b         36→60               "      "       "     "    "    5   20    9.sup.b         36    0.00046                      A, 0.00046                              "     "    "    10  10.3    10.sup.b         60    "      "       "     "    91   10  20    Toluene    11.sup.c         -20→-17               0.00057                      A, 0.00057                              30    6.3  65   60  1.3    12.sup.c         25→38               0.00077                      D, 0.00038                              "     "    "    10  2.5    13.sup.c         24→5               0.00057                      MAO, 0.057                              "     "    20   15  3.3    14.sup.c         28→34               0.00057                      MAO, 0.057                              "     6.3  5    135 11.0    __________________________________________________________________________     .sup.a  DTBP! = 0.0045 mol/L;     .sup.b  TEAL! = 0.0019 mol/L;     .sup.c  TEAL! = 0.0010 mol/L;    A: dimethylanilinium tetrakisperfluorophenylboron;    D: triphenylmethyl tetrakisperfluorophenylboron;    MAO: methylalumoxane 30 wt. % in toluene; note molarities based on     V.sub.solvent + V.sub.IB ;     .sup.d chlorobenzene was used in place of toluene as solvent.

                                      TABLE 2    __________________________________________________________________________    Polymer Characterization                       PIB   mol % IB in         GPC GPC  GPC  wt. % P(E-co-IB)                                    T.sub.g                                       T.sub.m                                          DH    Example         M.sub.n             M.sub.w /M.sub.n                  modality                       (.sup.1 H-NMR)                             (.sup.1 H-NMR)                                    (°C.)                                       (°C.)                                          (J/g)    __________________________________________________________________________    1      8000             4.2  1    y     25     ND ND ND    2      760             7.1  1    y     42     -73                                       -- --    3    --  --   ND   none  31     ND ND ND    4    --  --   ND   "     ND     ND ND ND    5    10,300             2.5  1    "     33     ND ND ND    6    12,300             2.0  1    "     ND     ND ND ND    7    26,500             2.3  1    "     24     ND ND ND    8      2060             6.2  2    "     31     ND ND ND    9      3260             6.5  2    "     11     ND ND ND    10   16,670             8.5  2    "     4      ND 129                                          122.3    11   48,500             1.7  1    "     31     -36                                       127                                           4.8    12     8910             2.2  1    "     33     -36                                       127.sup.e                                           11.0    13   14,500             2.0  1    "     38     -31                                       111                                          ND    14   13,200             2.5  1    "     45     -25                                       ND ND    __________________________________________________________________________     .sup.e T.sub.m1 = 15.4° C., 0.34 J/g;    ND: not determined

Example 11

This polymerization was run similarly to examples 3-6 except for the useofTEAL as scavenger and a polymerization temperature of -20° C. Thepolymerization was run for 1 hour.

Example 12

This polymerization was run similarly to examples 1 and 2 except for theuse of two molar equivalents of metallocene to one molar equivalent ofPh₃ CB(pfp)₄.

Examples 13 and 14

These polymerizations were run similarly except for using TEAL asscavenger, methylalumoxane MAO) as activator, and lower ethylenepressure.

Examples 15 and 16

These polymerizations were run similarly to examples 7-10, but withdifferent metallocenes.

Example 17

This polymerization was run similarly to examples 7-10, however, 100 mlof 2-methyl-1-pentene was used in place of isobutylene.

Example 18

Toluene (30 ml) and 0.06 ml of a 1.0M TEAL solution were combined, agedfor5 minutes and cooled to -50° C. At this temperature, 30 ml ofliquidisobutylene was added. The reactor was sealed and warmed to 25° C.The pressure of the reactor was increased an additional 5 psi with theaddition of ethylene. Separately, 15 mg ofdimethylsilyl(tetramethylcyclopentadienyl)(cyclododecylamido)titaniumdimethyl was activated with 657 mg of a 30 wt% methylalumoxane solutionintoluene. This solution was added to the catalyst chamber and added tothe reactor with nitrogen back pressure. Immediately, the pressure wasraised an additional 20 psi with propylene addition. The reaction wascontinued for 15 minutes. The reactor was depressurized and the reactionquenched with methanol. Polymer was isolated with methanolprecipitation. Yield: 2.0 grams. The terpolymer had a M_(n) of 7770 anda M_(w) /M_(n) of 3.4. A ¹³ C-NMR (62.5 MHz) spectrum revealed that theterpolymer consisted of 76 mol % propylene, 13 mol % ethylene and 11 mol% isobutylene.

                                      TABLE 3    __________________________________________________________________________    Polymerization Conditions with other Mono-CpTi         Temperature               Catalyst                      Activator                              Hexane,                                     IB! Ethylene                                              time                                                  Yield    Example         (°C.)                cat.!, (mol/L)                       act.!, (mol/L)                              volume (ml)                                    (mol/L)                                         (psi)                                              (min.)                                                  (grams)    __________________________________________________________________________    15   60    Q, 0.00070                      A, 0.00046                              100   6.3  91   5   32.5    16   60    F, 0.00046                      A, 0.00046                              100   6.3  91   10  2.74    17   60    F, 0.00046                      A, 0.00046                              100    2.0*                                         91   10  3.8    __________________________________________________________________________    for all runs  TEAL! = 0.0019 mol/L;    Q: dimethylsilyl(methylcyclopentadienyl)(tbutylamido)dimethyltitanium;    F: dimethylsilyl (methylcyclopentadienyl)(cyclododecylamido)     titaniumdimethyl;    *concentration of 2methyl-1-pentene.

                                      TABLE 4    __________________________________________________________________________    Isobutylene/Ethylene Copolymerizations    Polymer Characterization                           mol % IB in                       PIB P(E-co-IB)                                  T.sub.g                                     T.sub.m                                        DH    Example         M.sub.n             M.sub.w /M.sub.n                  modality                       wt. %                           (.sup.1 H-NMR)                                  (°C.)                                     (°C.)                                        (J/g)    __________________________________________________________________________    15   13,760             4.8  1    none                           1.0    ND 127                                        148    16     5600             3.91 1    "   4.0    ND ND ND    17   10,780             5.86 1    "    9.0*  ND ND ND    __________________________________________________________________________    ND: not determined;    *mol % of 2methyl-1-pentene incorporation by .sup.13 CNMR

Example 19

This polymerization was run similarly to examples 7 to 10 except that 13mgofdimethylsilyl(tetramethylcyclopentadienyl)(tert-butylamido)zirconiumdimethyl was used and activated with 27 mg of dimethylanilinumtetrakisperfluorophenylboron. A differential pressure of 91 psi ofethylene was used with a reactor temperature of 60° C. Polymerizationwas stopped after 30 minutes to produce 41.76 g of copolymer. ¹ H-NMR(250 Mhz) spectrum of this copolymer revealed thatthe copolymercontained 2.4 mol % isobutylene.

The following examples are given as comparative examples.

Example A

This polymerization was run similarly to example 13 except for higherethylene pressure and a change in the metallocene. Toluene (30 ml) and0.06 ml of a 1.0M TEAL solution were combined in the reaction chamberand aged five minutes. The reactor was cooled to -20° C., whereupon 30ml of isobutylene was added. The reactor was sealed and warmed to 25° C.Ethylene was added to 40 psi. Separately, 7 mg (0.00024 mol)ofpentamethylcyclopentadienyl titanium trichloride was activated in 484mg(0.0025 mol Al) of a 30 wt.% MAO solution in toluene. The activatedcatalyst solution was pressurized into the reactor with 65 psi ofethylene. Reaction was continued for 15 minutes. No polymerization wasobserved.

Example B

Chlorobenzene (40 ml) and 20 ml of isobutylene were combined into thereaction chamber at -20° C. The reactor was sealed and pressurized to 40psi with ethylene. Separately, 12 mg (0.00003 mol) ofbis(pentamethylcyclopentadienyl)zirconium dimethyl and 28 mg oftriphenylmethyl tetrakisperfluorophenylboron were reacted together in 2mlof chlorobenzene. This solution was placed into the catalyst additionport and added to the reactor with 60 psi nitrogen back pressure. Thereaction exothermed to 35° C. Reaction continued for 30 minutes. Thevessel was de-pressurized and methanol added to end the reaction.Polymer was isolated by methanol precipitation. The product (1.4 grams)was analyzed by ¹ H-NMR to be a blend of polyethylene andpolyisobutylene.

Example C

Toluene (30 ml) and 0.06 ml of a 1.0M TEAL solution in hexanes werecombined and aged 5 minutes. This solution was cooled to -80° C.,whereupon 30 ml of isobutylene was added. The reactor was sealed andwarmed to 25° C. Separately, 10 mg ofdimethylsilyl-bis(tetrahydroindenyl)zirconium dimethyl was dissolvedinto 2 ml of toluene and activated with 500 mg of a 30 wt.%methylalumoxane solution in toluene. The activated catalyst solution wasadded to the catalyst addition port of the reactor. The catalyst wasadded to the reactor with nitrogen back pressure. Ethylene wasimmediately added to addan additional 40 psi to the reactor pressure.The reaction was continued for 25 minutes. The polymerization wasstopped by de-pressurizing the reactor and quenching with methanol. Thepolymer was isolated by filtration and washed with methanol beforedrying in vacuo. This polymer contained 0.5 mol. % isobutylene. Yield:0.75 grams.

We claim:
 1. A substantially random ethylene copolymer derived from ethylene and at least one geminally disubstituted olefin monomer comprising from about 11 mole percent to about 50 mol % of the at least one geminally disubstituted olefin monomer.
 2. The copolymer of claim 1 wherein said at least one geminally disubstituted olefin monomer has the generic formula

    R.sub.1 =R.sub.2 (R.sub.3)(R.sub.4),

where R₁ is CH₂, R₂ is C, and R₃ and R₄ are, independently, hydrocarbyl groups having from 1 to 20 carbon atoms and containing one carbon atom bound directly to R₂.
 3. The copolymer of claim 1 having terminal vinylidene unsaturation.
 4. The copolymer of claim 1 having a number-average molecular weight of from 300 to 100,000.
 5. The copolymer of claim 3 having a number-average molecular weight of from 300 to 10,000.
 6. The copolymer of claim 1 additionally comprising at least one coordination polymerizable monomer other than ethylene and said at least one geminally disubstituted olefin monomer.
 7. The copolymer of claim 1 wherein said geminally disubstituted olefin monomer is isobutylene or 2-methyl-1-pentene.
 8. The copolymer of claim 2 wherein said geminally disubstituted olefin monomer is isobutylene or 2-methyl-1-pentene.
 9. The copolymer of claim 6 wherein said at least one coordination polymerizable monomer is selected from the group consisting of: C₃ and higher α-olefins, styrene and hydrocarbyl-substituted styrene monomers wherein the substituent is on the aromatic ring, C₆ and higher substituted α-olefins, C₄ and higher internal olefins, C₄ and higher diolefins, C₅ and higher cyclic olefins and diolefins, and acetylenically unsaturated monomers.
 10. The copolymer of claim 6 wherein said at least one coordination polymerizable monomer is selected from the group consisting of propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 4-methyl-1-pentene, 5-methyl-1-nonene, 3-methyl-1-pentene, 3,5,5-trimethyl-1-hexene, vinylcyclohexane, styrene, paramethylstyrene, ethylidene-2-norbornene, vinylcyclohexene, 5-vinyl-2-norbornene, norbornene, and alkyl-substituted norbornenes.
 11. The copolymer of claim 6 wherein said at least one coordination polymerizable monomer is selected from the group consisting of propylene, 1-butene, 1-hexene, 1-octene, styrene, and norbomene. 